Mini Toolbar/Quickbar unavailable if fullscreen changed to other host screen

Description

I am using 4.0.2 on Windows Vista host. (guest should be irrelevant, but is linux in case)

My host has 2 Monitors.
The guest has one Monitor, and runs fullscreen.

The mini-toolbar appears on the bottom of the screen.

If I switch (vie mini-toolbar "view" / "virtual screen" / "use host screen x" to the other host screen, then the mini toolbar will no longer appear, if the mouse is moved to the bottom-middle position.

Switching temporarily to window mode, and back to fullscreen fixes the issue (as a work around) until the next host-monitor switch